My laptop screen is grey and won't change

Registration date
Monday September 21, 2015
Last seen
September 21, 2015
Hi all!
My dell Inspiron N5110 would start but the screen wont change from grey. If i switch it off for 4-5 hours and turn it on i cannot see the dell logo but after a minute the windows welcome screen appears and i can log into my account but after 5-10 minutes the screen goes grey on its own.

P.S. i tried pressing F2/F8 to go to the boot menu but it doesn't happen(even if it does i cannot see it because of the grey screen)

Please help!
Thanks in advance.